1. Technical Field
This disclosure generally relates to systems and methods for processing fish, and more particularly to systems and methods for cutting the belly of a fish, severing the gullet connection to the body of the fish and removing the viscera from the body without significant damage to the body or the viscera.
2. Description of the Related Art
In some fish products, the head is removed at the gills, leaving a hard cartilage structure on the head end of the fish called the collar. The viscera, including the gonads (roe or milt) are removed, the kidney membrane is cut and the kidney is removed with water sprays and brushes. In the salmon industry, this product is called a head and gut product which is a valuable commodity. In recent years the value of intact roe (female gonads) has also increased making it a valuable commodity as well. However, if the roe skein is cut or otherwise damaged, the value of the roe is greatly diminished. Some markets also value the undamaged milt (male gonads).
In many fish, including salmon, the gullet is attached only to the collar, and the viscera are firmly attached only to the gullet and the anal vent or anus. In most fish caught in saltwater, where the highest volume of commercial fish is caught, the connection of the viscera to the vent is not strong, and is easily broken when cleaning the fish. Disconnecting the gullet from the collar, however, is significant to proper cleaning of most fish, and significant to avoiding damage to the gonads.
Machines for cutting open the belly, removing the viscera and cleaning the belly cavity have been in use for many years. Some machines require detaching the gullet from the body prior to processing. Some allow the gullet to be intact before processing, but do not reliably remove the gullet. When the gullet is not cut free or does not break free from the body during processing, the remainder of the viscera does not separate from the fish, the valuable roe or milt is damaged and the fish is not cleaned properly, thereby increasing labor costs and downgrading value of the fish product.
Example systems and methods for processing fish are described in U.S. Pat. Nos. 3,925,846; 4,563,793; 4,630,335; 5,352,152; and 5,413,524.
While known systems have been generally effective to process fish, the systems suffer from various deficiencies and shortcomings, such as, for example, inadvertent damage to the gonads or remaining fish structure during processing which diminishes the value of the processed fish and/or recovered fish parts. As another example, many known systems are incapable of effectively adjusting to variations in the size, shape and/or firmness of the fish being processed in a reliable and repeatable manner.